The invention relates to a device for the infeed of discrete strips of tin foil in cigarette packaging machinery.
In conventional cigarette packaging machinery, bundles of cigarettes are formed internally of the single pockets of a conveyor, each bundle normally formed of twenty cigarettes stacked in three layers, and fed in succession to an indexing head generally provided with two slots, each one of which designed to accommodate a relative bundle of cigarettes. Once positioned in a relative slot, each of the single bundles of cigarettes is transferred, by rotation of the indexing head about its own axis, to a folding station at which discrete strips of tin foil arrive in steady succession. The single bunch of cigarettes occupying the folding station is normally ejected from the slot in a radial direction, urged against the relative strip of foil in such a way that foil and cigarettes are transferred, as one, into the peripheral radial pocket of a wrapping wheel, with the foil assuming a U profile and enveloping the bundle of cigarettes as the two are urged into the pocket.
In conventional packaging machinery, infeed of the discrete strips of tin foil to the folding station is accomplished by a cut-and-feed device that operates wholly independently of the indexing head, and will generally incorporate at least one cutting head, which severs the discrete lengths of tin foil from continuous bulk strip, and a plurality of feed rollers that convey the discrete strips toward the folding station.
It has been observed in practical application that certain factors, namely, operation of the feed rollers, channelling and alignment of the discrete strips of tin foil, and above all, timing between infeed of the wrapping strips and arrival of the bundles of cigarettes at the folding station, become increasingly difficult to control as the production tempo of the packaging machinery is stepped up.